NEW YORK (Reuters Health) - Kids who start rapidly gaining
weight early in childhood are more likely to have higher blood
pressure and other signs of future heart trouble as preteens, a
new study suggests.

"There's a natural tendency early in life for children to
thin out as they grow taller and gain stature faster than they
gain weight," Dr. Mark D. DeBoer said.

But eventually, all kids hit a point when they start gaining
weight at a faster pace, and their body mass index (BMI) - a
measure of weight in relation to height - begins to rise. That
point is called the adiposity rebound.

The adiposity rebound typically happens around age four to
six, DeBoer, who studies childhood obesity at the University of
Virginia in Charlottesville, told Reuters Health.

Some studies have suggested children who start to put on
weight at a younger age are more likely to be obese later in
life. The new report adds to those concerns.

"It helps I think give us a better understanding of what
this might be impacting in addition to obesity," Dr. Stephen
Daniels said.

Daniels studies preventive cardiology at the University of
Colorado School of Medicine in Aurora, where he chairs the
Pediatrics Department. Neither he nor DeBoer was involved in the
new study.

Researchers led by Dr. Satomi Koyama of Dokkyo Medical
University in Mibu, Tochigi, Japan, followed 271 children born
in 1995 and 1996. Kids had their weight and height measured at
least once every year through age 12 during infant health checks
and then physical exams at school.

From looking at each child's growth pattern, the researchers
determined when children hit their lowest BMI, the age at
adiposity rebound. After that, they got bigger every year.

Koyama's team found the earlier both boys and girls reached
that turning point, the heavier they were at age 12.

For instance, boys who started getting bigger around age
three had an average BMI of 21 as preteens. That's the
equivalent of a five-foot-tall boy weighing 108 pounds.

Boys who didn't start getting bigger until at least age
seven had an average BMI of 17 - the equivalent of the same boy
weighing 87 pounds.

Boys who had their adiposity rebound at a young age also had
higher triglycerides and blood pressure at age 12. Although
their numbers were still in the normal range, they could hint at
signs of future heart problems, the researchers wrote Monday in
Pediatrics.

For girls, the link between age at adiposity rebound and
heart risks was smaller but still visible.

"Physicians should be tracking body mass index and should be
checking for kids who are headed in the direction of being more
obese," Daniels said.

But, he told Reuters Health, parents and pediatricians won't
be able to tell exactly when children are at their adiposity
rebound. And it's not clear how to prevent it from happening
early.

"There's a strong possibility that these are children who
inherited a genetic predisposition that made them more likely
both to have early adiposity rebound and to have metabolic
syndrome earlier in life," DeBoer said.

Metabolic syndrome is a cluster of risk factors, including
high blood pressure, that are linked to heart disease.

"The message is probably still more general, in terms of
families working with pediatricians and family physicians to
make sure that families have a healthy diet (and) that they have
healthy opportunities for activity," Daniels said.